| Type: | monarch |
| Kilij Arslan IV | |
| Succession: | Sultan of Rum |
| Reign: | 1246/1249–1254 (first rule) 1257–1266 (second rule) |
| Predecessor1: | Kaykhusraw II |
| Successor1: | Kayqubad II |
| Predecessor2: | Kayqubad II |
| Successor2: | Kaykhusraw III |
| Regent: | Kayqubad II (1249–1254) Kaykaus II (1249–1254) and (1257–1262) |
| Reg-Type: | Co-sultans |
| Full Name: | Rukn ad-Dīn Qilij Arslān ibn Kaykhusraw |
| House: | Seljuk |
| Spouse: | Gumaḉ Khatun Fatima Khatun Gazalya Khatun |
| Issue: | Saljuk Khatun, Kaykhusraw III |
| Father: | Kaykhusraw II |
| Mother: | A Greek concubine |
| Birth Date: | 1237 or 1240 |
| Death Date: | 1265 (aged 25 or 28) |
| Religion: | Islam |
Kilij Arslan IV (قِلِج اَرسلان) or Rukn ad-Dīn Qilij Arslān ibn Kaykhusraw (fa|رکن الدین قلیچ ارسلان بن کیخسرو) was Seljuk Sultan of Rûm after the death of his father Kaykhusraw II in 1246.
However, a jarlig issued by Güyük Khan confirmed him as sultan over his elder brother, Kaykaus II in 1248. But this jarlig would quickly be worthless after Güyük's death in the same year. Later, Arslan's supporters killed Shams al-Din Isfahani, a supporter of his brother, Kaykaus II (a rival to the throne). The death of Isfahani's successor in 1254, Jalāl-al-Din Qaraṭāy, left a power vacuum which was filled by competition by supporters of the two brothers. Eventually, Kaykaus II would emerge the victor in 1256.[1]
In the 1260s, Mu'in al-Din Parwana redistributed Seljuk crown lands among his followers. He did this to secure his position but would be met with protests from Arslan. This eventually led to Arslan's execution in 1265 by Parwana.